Titania is one of the world's most demanded chemicals because of the high versatility of its uses. For example, it is used in such things as paints, coatings, sunscreens, glass, synthetic fibers, paper, implants for humans, and as a germicidal agent for the treatment of wounds. In recent years, nanocrystalline titania has attracted significant attention because of its photocatalytic property in applications such as: the removal of organic and inorganic pollutants from air and water; the killing of bacteria; a photovoltaic material for harvesting solar energy; in the photoreduction of nitrogen and carbon dioxide; and as a dielectric material for ultra thin capacitors. While titania is sometimes sprayed on wounds in order to decrease infection, it cannot be extracted with the use of a magnetic field because it is an insulator. It is generally known that composite particles can be formed comprised of a magnetic core with a titania outer layer to aid its extraction when used in such uses as the treatment of wounds. Ma et. al., Synthesis and Characterization of Titania-Coated Mn—Zn Ferrite Nanoparticles; Colloids and Surfaces A: Physicochem. Eng. Aspects 224 (2003) 207-212 teaches a core-shell structured composite comprised of titania coated Mn—Zn ferrite nanoparticles.
U.S. Pat. No. 5,770,172 discloses a process for forming nano-sized metal compounds using reverse micelle or reverse microemulsion systems. The nano-sized metal, preferably Fe-compounds, are produced for use as catalysts for the conversion of coal to liquid and gaseous products.
While the art teaches titania shell/magnetic core nanoparticles and their preparation, there is still a need in the art for more efficient and economical methods for preparing such compositions. There is also a need in the art for titania shell/magnetic core composite nanoparticles having improved magnetic properties.